Electromagnetic hammer



y 6, 1929. B. H. PARKER ET AL 1.720.854

ELECTROMAGNETIC HAMMER Filed Aug. 22, 1927 4 Sheets-Sheet l \u/ Ill/AW /5 E B} M 14 nor qy July 16, 1929 B. H. PARKER ET AL 1.720.854

ELECTROMAGNET I C HAMMER Filed Aug. 22, 1927 4 Sheets-Sheet 2 E1 29 l' 4 20 z l I Q r e Inventors /9 jaw fli ar/ren' 14 ttornqy B. H. PARKER ET AL ELECTROMAGNETIC HAMMER July 16, 1929.

Filed Aug. 22, 1927 4 Sheets-Sheet July 16, 1929. PARKER ET AL 1,720,854

ELECTROMAGNETI C HAMMER Filed Aug. 22, 1927 4 Sheets-Sheet 4 1p MM wherein ance, strong and durable,

Patented July 16, 19 29.

UNITED STATES PATE NT OFFICE. 1

' BEN H. PARKER ANDCLARENCEV DONALD IBEETH, JR, or LAMAR, COLORADO.

ELECTROMAGNETIC 'HAMMER.

Application filed August 22, 1927. Serial m. 214,646.

This invention relates to electro-magnetic hammers and is adapted particularly for use in connection with hammer type rock drills, riveting machines, chiseling machines, and other machines using a hammer blow during the operation thereof. An important object of the invention is to provide a reciprocally mounted hammer arranged for actuation by a series of electro-magnets and embodying a pneumatic cushioning construction adapted] to arrest the return stroke of the hammer;

Another object is to provide an apparatus of this characterof-simple and practical construction, eflicient and reliable in perform- 1 and otherwise well adapted for the purposes for which the same is intended. 1

7 Other objects and advantages reside in the special construction and combination of the various elements forming a part of the invention, reference being had to the accompanying drawings forming apart hereof,

Figure 1 is a view in elevation with parts shown in vertical section illustrating the relagive position of the electro-magnetic memers- Figure 2 is a similar View showing the device in side elevation.

Figure 3 is a transverse sectional View taken substantially along a. line '3-3 of Figure l.

Figure 4. is a similar view 'taken along a line 4-4 of Figure 1. 1

Figure 5 is a similar view taken along a line 5- 5 of Figure 1.

Figure 6 is a similar view taken along a line 6-6 of Figure 1.

Figure 7 is a group perspective of the electric contact sleeves and the insulation sleeve interposed therebetween.

Figure 8 is a detail illustrating the manner of connecting the sleeves-with the armature core, and,

Figures 9 and 10 are diagrammatic views illustrating opposite magnetic effects produced by reversing the direction of the current in order to obtain the reciprocating movement of the hammer; I,

Referring to the accompanying drawings, we have disclosed our invention comprising a substantially cylindrical housing 5, preferably constructed of suitable light weight metal such as aluminum, and having its lower end closed by a base plate 6 and its shank 17 is retained in immediately above with. The

upper'end closed by a head plate 7. Ears 8 i ing coil springs 11 disposed above and be neath the The upper end of the studs are connected by a cross member 12 having a handle 13 mounted thereon.

The base plate 6 is provided with a cen? tral opening about which is formed a bushing guide 14 having a tool chuck bushing 15 fitted therein and adapted to carry a tool chuck 16 therein The tool chuck is adapted to receivea tool shank 17 having a drilling or other tool such as a bit 18 or the like formedat its lower end. The tool position within the chuck by means of a tool retainer clip 19 having one end adapted to embrace the tool and having its opposite end secured to a retainer clip mounting 20 disposed beneath the base plate 6, said 1 clip mounting and base plate having alined openings formed therein for receiving rods 21 extending from the head plate 7 and secured in position with respect thereto by threaded nuts 22. Coil springs 23 are mounted on the lower ends of the rods whereby to tensionally secure theretainer 'clip mounting in position A striking hammer 24- is centrally arranged Within the housing 5 and disposed the upper end of the tool shank 17 and adapted to be moved into and-out of striking engagement therewith. The hammer 24 is carried by a movable electro-magnet formed of an armature core 25, which is of magneti material and hav-' ing a central bore for receiving an armature shaft 26 in slidable engagement thereupper end. of the armature shaft extends through the headplate 7 and is fixedly secured With respect thereto by a nut 27 and which is threaded on the upper end of said shaft. 1

Fixedly secured to the upper end of the armature core is disposed apair of cylindrical concentrically mountedsleeves 28 and 29, the upper ends ofthe sleeves being open permitting the same to be arranged in nested relation, the numeral 28 indicating the inner sleeve, and the numeral 29 indiplates whereby to yieldably permit sliding movement of the studs therein.

*cating 'the outer sleeve. An insulation sleeve 30 is interposed between the sleeves 28 and 29. Each of the sleeves is provided with a central opening in the lower end thereof through which the armature shaft 26 is inserted and bolts 32 secure the lower ends of the sleeve to the upper ends of the armature core 25. The sleeves 28 and 29 are formed of conductive material'and have an insulation plate 33interposed therebetween and' the armature core to prevent electrical communication .therebetween.

Upon the armature shaft 26 is mounted I an insulated brush holder 34 supporting a contact brush 35 yieldably'retained in con-' tacting relation with the base of the inner sleeve 28 and a similar brush holder 36 is' secured adjacent the outer face of the outer sleeve 29 having a contact brush 37 likewise yieldably contacting therewith. Electric wires 38 extend from the brushes outwardly der to enhance the magnetic quality thereof, the ends of the sections forming the poles being joined as by welding at points indicated at 40. Y

The intermediate section of-the poles constitutes a field magnet core shown at 41 about which is arranged an upper field magnet winding 42 and a lower field magnet wmdmg 43. At each end of the windings 42 and 43 and arranged in magnetic connection with the field magnet core 41 are transversely arranged field magnet poles 44,.

saidfield magnet poles extending throughout the area within the housing 5 except for the openings necessary for the vertical .shdlng movement of the sleevesand the armature core. In the present form of this invention while we have indicated the use of a; pair of such field magnet units, each consisting of a field magnet core'41, windlugs 42 and 43,and necessary'lead-in wires 45, it is to be understood that the number of such units employed for use with the v invention may be increased or decreased as desired. Field coil lead-in wires 45 connect the same with a suitable source of current. i

The armature core 25 is provided with a suitable armature winding 46, a suitable electrical connection 47 being arranged to connect said winding with the contact sleeves 28 and 29. To energize the armature, current isfed from the source of supply through one of the armature winding lead-in wires, then to one of the brushes35 or 37, contacting with the sleeves. 28 and 29, then by way of the electrical connection 47 to the arma ture winding and out through the other armature winding connection and back to the source of supply.

The field magnet windings may be connected in series, in parallel, or in a combination of series and parallel in order to set up themagnetic field as illustrated in Figures 9 and 10 of the drawings when current is supplied to the field coil lead-in wires.

The reciprocating movement of the annature carrying the striking hammer 24 is obtained by reversing the direction of current flow in either the field coils or the armature coil, but notboth, and may be accomplished in any suitable manner, a practical method of obtainingthis result being shown by the rotating commutators illustrated in Figs. 9

and 10, consisting of a pair of conductive mounted upon and insulated from a rotating shaft 49 together with four fixed brushes current reversing mechanism is a separate unit from the electro-magnet hammer proper and may be installed adjacent to or at a remote distance from the hammer itself. The rotation of the shaft 49 "upon which the armatures are mountedis obtained by any desired motive power, preferably an electric motor. The number of hammerblo'ws imparted to-the striking hammer 24 carried by the armature, in an allotted time, is a functionof the number of revolutions, in such allotted time, of the current reversing mechanism. If desired, the two conductive rings of such current reversing mechanism may be so shaped and proportioned that the pe- -rings 48, insulated from each other and arranged and connected as shown. This riod of current flow which causes the hammer blow will be of a longer duration than the period of' current flow which causescthe return stroke of the striking hammer. This action, in effect, would cause a magnetic cushioning for the striking hammer on its return stroke. I v v However,a more posltive cushioning arrangement is provided for the striking hammer .consisting of a pocket of air entrapped within the space between the lower ends of the armature shaft 26 and the striking hammer 24, as indicated at 51 and having a plurality of air ducts 52 communicating there- 'air ducts 52 maybe provided and arranged in such a position as to allow the partial return of the striking hammer without any ararrested and the magnetism is revesed to cause the movement of the striking hammer the hammer stroke, the compressed air within the cushioning device aids in the starting of the hammer stroke by tending to expand to its normal volume, and as soon as such volume has been reached the air ducts then occupy an open position with respect to the air pockets 51 sothat air is free to enter the same and allow the completion of the hammer stroke without resistance of any low pocket formed tible of various housing, a striking the actuation of the hammer.

housing, a strlking pressure within the pocket.

It is obvious that the invention is suscepchanges in the shape, size and arrangement of the various elements, without departing from the spirit or scope ofthe appended claims, and we accordingly claim all such forms of the device to which we are entitled.

e claim 1, In a device'of the class described, a

hammer arranged therein, a tool extending within the housing in striking engagement with said hammer, electro-magnetic means arranged within the housing 0 ratively connected with said hammer w ereby to reciprocally actuate the same, said hammer having an air pocket formed thereln with alr'ducts communlcating therewith and adapted to be closed by the upward movement of the hammer where by to cause an air pressure within the pocket and arranged to react upon the hammer whereby to cushion the upward movement thereof. a v

2. In a device of the class described, \a housing, a striking hammer arranged therein, a tool extending within the housing in striklng position electro-magnetic operating means for said hammer and arranged to-reciprocally actuate the same, said hammer having an air therein with air ducts communicating therewith and arranged to be closed by the movement of the hammer. in one direction and creatin an air pressure within the pocket where to serve as a cushioning means limiting the movement of the hammer in such direction and adapted through the expansion of the air to facilitate 3. In a device of theclass hammer arranged there-' in, a tool extending through the housing in in a downward direction which constitutes with respect to said hammer,

forming a guide for the described, a

striking position with respect to said hammer, elect-romagnetic means adapted to reciprocally actuate said hammer, and comprising an armature core connected with the hammer, contact means secured to said core, an armature shaft extending through the sleeves and the core and arranged to slidably carry the latter, field coils disposed within the housing operatively arranged with respect to said an armature winding therefor,.

armature, an electrical connection for the armature and the field coil, means forreversing the flow of current therethrough, and a cushioning device for the striking hammer comprising an air pocket formed between the hammer and the armature shaft and having air ducts communicating there; with and adapted to be closed by the upward movement of the hammer whereby to cause the formation of an air pressure between the hammer and said shaf 4. In a device of the class described, a

housing, a striking hammer arranged therein, a tool extending through the housing in striking relation with said hammer, electromagnetic means operatively connected with said hammer, and adapted to reciprocally actuate the same and comprising an armature core attachedto the hammer, an armature winding therefor, an armature shaft fixedly secured to the housing and arranged to slidably carry said core, electric contact sleeves carried at the upper ends of said core, contact brushes for said sleeve, field coils arranged within the housi g and operatively disposed with respect to said armature, an electrical connection for the armature and said field coils, means for reversing the flow of current therethrough whereby to effect a reciprocal movement of the armature core. an air pocket formed between the lower end of the armature shaft and the striking hammer, air ducts extending through the armature core communicating with said pocket and adapted to be closed upon the upward movement of the hammer, such movement of the hammer operating to creates anair pressure within the medium between the shaft and the hammer to prevent striln'ng contact therewith and adapted through the expansion of the air to facilitate the actuation of the hammer in a diriection for striking engagement with the too t 5. An electro-magnetically operated ham mer including a series of stationary electro magnets and a movable armature operatively associated therewith and having a hollow core, a hammer head carried by the armature, said head forming a closure at the lower end of the core, a stationary shaft core and cooperating with the head to form an air compression chamber within the core, said chamber having air outlets extending through the pocket forming a cushioning wall of the core and controlled in their open and closed positions by the movement of the core upon the shaft.

6. An electro-magnetically operated ham-' mer comprising an electrically actuated movable member, a hammer head carried thereby, said member having a hollow core, a stationary shaft providing a slidable mounting for the core and cooperating with the hammer head and forming a compression chamber in the core, said chamber. having ducts extending through the wall thereof res.

CLARENCE DONADD BEETH, J R. BEN H. PARKER. 

